Proverbs 4:14 (NKJV) — 14 Do not enter the path of the wicked, And do not walk in the way of evil.
A wise person will not walk the same path as wicked people. Not only is there the danger of guilt by association, but there is also the detrimental influence of the ungodly.
Psalm 1:1 (NKJV) — 1 Blessed is the man Who walks not in the counsel of the ungodly, Nor stands in the path of sinners, Nor sits in the seat of the scornful;
This admonition does not imply that we should not attempt to win unbelievers to the Lord; it rather prohibits our uniting with them for common purposes that could lead us into evil.
2 Corinthians 6:14–18 (NKJV) — 14 Do not be unequally yoked together with unbelievers. For what fellowship has righteousness with lawlessness? And what communion has light with darkness? 15 And what accord has Christ with Belial? Or what part has a believer with an unbeliever? 16 And what agreement has the temple of God with idols? For you are the temple of the living God. As God has said: “I will dwell in them And walk among them. I will be their God, And they shall be My people.” 17 Therefore “Come out from among them And be separate, says the Lord. Do not touch what is unclean, And I will receive you.” 18 “I will be a Father to you, and you shall be My sons and daughters, says the Lord Almighty.”